Class 12MathematicsTHREE DIMENSIONAL GEOMETRYSystem of co-ordinates, Direction cosines and direction ratios, Projection
MediumIf $a, b, c$ are the direction ratios of a line $L$ and $\ell, m, n$ are its direction cosines,then $\frac{a^2}{b^2+c^2}=$
- A$\frac{1-\ell^2}{\ell^2}$
- B$\frac{\ell^2}{1+\ell^2}$
- C$\frac{\ell^2}{\ell^2+m^2}$
- D$\frac{\ell^2}{1-\ell^2}$
Explore More
Similar Questions
If a line makes angles $\alpha, \beta, \gamma, \delta$ with the four diagonals of a cube,then the value of ${\sin ^2}\alpha + {\sin ^2}\beta + {\sin ^2}\gamma + {\sin ^2}\delta$ is
Difficult
View SolutionIf the direction ratios of two lines are $5, -12, 13$ and $-3, 4, 5$,then the angle between them is:
Easy
View SolutionThe angle between the pair of lines with direction ratios $1, 1, 2$ and $\sqrt{3}-1, -\sqrt{3}-1, 4$ is $... ^\circ$.
Easy
View Solution$A$ line makes angles $60^{\circ}, 45^{\circ}, \theta$ with positive $X, Y, Z$-axes respectively. If $\theta$ is an acute angle, then $\tan \theta=$
If the direction cosines of two lines are such that $2l + m + 2n = 0$ and $3l^2 + 5m^2 - 11n^2 = 0$,then the angle between the two lines is
Vedclass Products
For Students
Vedclass Test Series
Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.
Start Free TrialFor Teachers
Exam Paper Generator
Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.
Try FreeFor Institutes
Online Exam Module
Live online exams with unlimited students, 360° analytics & white-label branding.
See Demo